The main difference between i386 and x86-64 smp boot up (among a lotof quirks and workarounds in i386 that x86-64 doesn't have/need andsome trivialities) is that x86-64 follows the standard hotplug statemachine and i386 doesn't.

I would suggest that if you want to unify you convert i386 over to the new state machine first because that is the key difference. Everything elseafter that is relatively simple. You can probably pattern that afterthe original changeset who did this for x86-64.

The reason I never attempted this myself is that i was too worried aboutregressions on old machines for i386 (this code is partly very fragile)You'll likely encounter that problem. Just make sure to keep a stableemail address for some years to handle the fallout.